Volumetric and dynamic OCT screening of human testicular tissue comparing unfixed and fixed samples

Prepubertal boys facing gonadotoxic therapies such as chemotherapy and radiotherapy can only preserve fertility by cryopreserving testicular tissue containing scarce spermatogonial stem cells (SSCs). However, reliable SSC-expansion- and in vitro-spermatogenesis-protocols are still lacking. To meet the growing need, research is focusing on organotypic testicular culture enhanced by microfluidics, using both limited prepubertal and more readily available adult testicular tissue to develop robust SSC propagation methods. In this regard, optical coherence tomography (OCT) was used to compare unfixed and fixed adult human testicular tissue in micro-well plates. A high-resolution 880 nm OCT system delivered near-cellular resolution, while a device at 1300 nm central wavelength offered deeper light penetration. Dynamic speckle contrast highlighted seminiferous tubules in the unfixed samples, whereas fixation increased bulk scattering, enhancing structural contrast. In the future, an OCT platform can enable rapid, non-destructive assessment of testicular microarchitecture and SSCs content for high-throughput sample screening and the development of methods to enable human in vitro-spermatogenesis.